Behaviors of Microcystis aeruginosa cells during floc storage in drinking water treatment process.

Hangzhou Xu,Jiongming Sun,Xiuqing Li,Chunxia Ma,Hongdi Xiao,Hongmin Li,Yan Jin,Haiyan Pei,Wenrong Hu

doi:10.1038/srep34943

Hangzhou Xu, Jiongming Sun + Show 7 more

Open Access

https://doi.org/10.1038/srep34943

Copy DOI

Journal: Scientific Reports	Publication Date: Oct 7, 2016
Citations: 34	License type: CC BY 4.0

Affiliation: Shandong University

Abstract

This is the first study to systematically investigate the different behaviors of Microcystis aeruginosa in the sludges formed by AlCl3, FeCl3, and polymeric aluminium ferric chloride (PAFC) coagulants during storage. Results show that the viability of Microcystis aeruginosa in PAFC sludge was stronger than that of cells in either AlCl3 or FeCl3 sludge after the same storage time, while the cells’ viability in the latter two systems stayed at almost the same level. In AlCl3 and FeCl3 sludges high concentrations of Al and Fe were toxic to Microcystis aeruginosa, whereas in PAFC sludge low levels of Al showed little toxic effect on Microcystis aeruginosa growth and moderate amounts of Fe were beneficial to growth. The lysis of Microcystis aeruginosa in AlCl3 sludge was more serious than that in PAFC sludge, for the same storage time. Although the cell viability in FeCl3 sludge was low (similar to AlCl3 sludge), the Microcystis aeruginosa cells remained basically intact after 10 d storage (similar to PAFC sludge). The maintenance of cellular integrity in FeCl3 sludge might be due to the large floc size and high density, which had a protective effect for Microcystis aeruginosa.

Highlights

This is the first study to systematically investigate the different behaviors of Microcystis aeruginosa in the sludges formed by AlCl3, FeCl3, and polymeric aluminium ferric chloride (PAFC) coagulants during storage
Coagulant species have a significant effect on the cell viability and integrity of M. aeruginosa cells during sludge storage processes
Because high concentrations of Al and Fe are toxic to M. aeruginosa, while appropriate amount of Fe is beneficial to the growth of M. aeruginosa, the M. aeruginosa cells in PAFC sludge have higher cell viability than those in AlCl3 and FeCl3 sludges after the same storage times

Summary

Introduction

This is the first study to systematically investigate the different behaviors of Microcystis aeruginosa in the sludges formed by AlCl3, FeCl3, and polymeric aluminium ferric chloride (PAFC) coagulants during storage. Results show that the viability of Microcystis aeruginosa in PAFC sludge was stronger than that of cells in either AlCl3 or FeCl3 sludge after the same storage time, while the cells’ viability in the latter two systems stayed at almost the same level. The cell viability in FeCl3 sludge was low (similar to AlCl3 sludge), the Microcystis aeruginosa cells remained basically intact after 10 d storage (similar to PAFC sludge). Coagulation, the key step in conventional drinking water treatment for pollutant removal, has been verified as an effective approach to remove intracellular toxins with intact cells, without causing additional release of intracellular toxins[12,14]. In the treatment of cyanobacteria-containing drinking water sludge, damage to cyanobacterial cells will result in the release of intracellular material, especially toxins, into the recycled water, increasing the burden of toxin removal[17]. How do cyanobacteria cells behave when transferred to the sludge? Up to now, little attention has been drawn to it

Methods

Results

Conclusion